In recent years, HDMIs (High Definition Multimedia Interfaces) have been widely used as digital interfaces connecting CE (Consumer Electronics) devices, and have become a de facto standard in the industry. Non-Patent Document 1 discloses the HDMI Specification, for example. According to the HDMI Specification, video, audio, and control signals are transmitted as digital signals by using three data differential line pairs (TMDS Channels 0/1/2).